1. Field of the Invention
The present invention relates to a method of thin printed circuit board wet process consistency on the same carrier and more particularly, to a continuous auto-consistent wet process method for enhancing the efficiency of the printed circuit board wet process by means of the same frame as a carrier.
2. Description of the Related Art
The process of a printed circuit board (PCB) includes a dry process and a wet process, wherein the printed circuit board requires immersing in different liquid in the wet process. For example, the printed circuit board requires being sprayed the developer in the developing process after the exposure process, and the printed circuit board requires being sprayed the rinsing fluid in the rinsing process, and so as the follow-up of plating, stripping, etching and other processes within the wet process.
The manufacturing method of the printed circuit board wet process can be broadly divided into two ways, horizontal production and vertical production. The so-called horizontal production as shown in FIG. 1 illustrates a developing process device 10 including a loading unit 11, a first developing unit 12, a second developing unit 13, a rinsing unit 14, a drying unit 15, a baking unit 16 and an unloading unit 17. The printed circuit board is conveyed through aforementioned various units by a conveying roller 18.
A slippery phenomenon sometimes happens between the conveying roller 18 and the printed circuit board resulting in the problems of sticking boards or stacking boards. When spraying the chemical liquid on the horizontal printed circuit board, the chemical liquid is easily left in the printed circuit board, resulting in so-called “water effect.” In other words, the horizontal machine will cause two types of effects; one effect is that the discharging speed of the liquid on an edge of the printed circuit board is faster than the center thereof. That is, the liquid on the center of the printed circuit board requires a longer distance for discharging, such that the liquid on the edge of the printed circuit board has discharged while the liquid on the center of the printed circuit board has not discharged yet and thus an accumulation of liquid is produced on the thin printed circuit board, such that the accumulation of the liquid lower the chemical reaction on the printed circuit board. Another effect is that the accumulation of the liquid affects the new liquid entering to the printed circuit board. That is, the liquid on the edge of the printed circuit board is thinner than the liquid on the center of the printed circuit board, thus the new liquid on the edge of the printed circuit board can easily enter into the printed circuit board and vice versa to cause a difference of chemical reaction speed.
Due to the printed circuit board are more and more precise now, it is easy to contact with the circuits and cause the damage of the circuits by using the roller to covey the printed circuit board and thus affects the production yield of the printed circuit board.
Another manufacturing method of the printed circuit board wet process is the vertical production method providing many printed circuit boards arranged in a matrix manner and being fixed on a rack, and then being moved to the designated treatment cell to conduct the wet process by a hoist.
In the traditional wet process such as developing, plating, stripping, and etching processes has separated device. For example, the developing process belongs to horizontal production, and the plating process belongs to vertical production. Thus, when moving the printed circuit board from the developing device to the plating device, the printed circuit board is easy to be scratched and damaged, more particularly to a thin printed circuit board or a soft printed circuit board. TW Patent No. M381635 as shown in FIG. 2 discloses a mainframe 20 serves as a carrier for copper plating on a printed circuit board 21. The contacted surface between the mainframe 20 and the printed circuit board 21 is large so the chemical liquid can be easily remained on the mainframe 20. If using one frame for one process or chemical liquid, it may not have the problem of cross-contamination between different cells. However, this kind of mainframe 20 does not apply to different processes thus cannot be used in a continuous process.
The non-continuous device is used in the conventional printed circuit board wet process, wherein the printed circuit board is conveyed through the developing device to plating device or to other devices by manual labor, resulting in higher cost and lower capacity. Therefore, there is room for improvement.